The present invention relates to a pulse combustor for pulsatively combusting fuel in a combustion chamber, and more specifically to a pulse combustor with a valve mechanism for controlling pulse combustion.
Pulse combustors of this type are generally provided with supply means for supplying air and fuel into a combustion chamber and a valve mechanism disposed in the combustion chamber or the up-stream side of the chamber. The valve mechanism, which serves as a one-way flow control valve for controlling the flow of air and fuel into the combustion chamber, includes a base plate disposed in the combustion chamber or the up-stream side of the chamber and having a plurality of gas supply holes, and a ring-shaped flapper valve, located on the base plate, for opening and closing the supply holes in accordance with the change of pressure inside the combustion chamber. At the start of the operation of the pulse combustor, air and fuel are fed into the combustion chamber by a blower, and ignited by an ignition plug to be deflagrated (or, caused to burn with intense heat). As a result, the pressure inside the combustion chamber increases to cause the flapper valve to be closed, so that the combustion gas is discharged through a tail pipe which communicates with the combustion chamber. When the combustion gas is exhausted, the pressure inside the combustion chamber becomes negative, so that the flapper valve is opened to allow the air and fuel to be automatically sucked into the combustion chamber. Also, part of the high-temperature gas discharged into the tail pipe flows back into the combustion chamber, and the air-fuel mixture gas int he combustion chamber is ignited and deflagrated b the high-temperature gas. Thereafter, the suction, ignition, expansion, and exhaust are automatically repeated for pulsative combustion.
When increasing the combustion volume in the prior art pulse combustors of this type, it is necessary to increase the volume of the combustion chamber and the number of air and fuel supply holes. Accordingly, the flapper valve is increased in size. Conventionally formed from a single plate, however, the flapper valve would become heavier with the increase of its size, resulting in unsmooth movement incompatible with pulse oscillation. Therefore, the combustion efficiency of the pulse combustor may be lowered, or the pulse oscillation would be interrupted. Since the surface area of the flapper valve is wide, various parts of the flapper valve act unevenly, resulting in the life of the flapper valve being shortened. Moreover, it would be rather difficult to start the operation of the pulse combustor.
Accordingly, the valve mechanism is conventionally divided into two or more segments. In this case, however, each segment requires all the essential components for an entire valve unit, including a base plate, flapper valve, valve guards, etc. As a result, the valve mechanism and hence the pulse combustor are increased in overall size and complicated in construction. Also, the segments would possibly interfere with one another, interrupting the pulse oscillation.